The long-range goal of this project is to provide quantitative, experimental information about the relationships which link molecular structure and molecular dynamics to the functions of biological macromolecules. To obtain such information we have developed novel and sensitive nuclear magnetic resonance (NMR) methods which use carbon 13, nitrogen 15 and their attached protons to probe macromolecular structure and dynamics in unique ways. These methods, some of which may ultimately find applications in biomedical imaging and spectroscopy, can provide the following: (1) ultrasensitive, indirect detection of carbon 13, nitrogen 15 resonances via proton NMR, (2) unambiguous values for the torsional angles of the peptide back bone (phi, psi) and the side chain residues (chi), (3) detailed kinetic parameters for the internal, anisotropic motions of side chain groups, (4) identification of solvent-exposed and solvent-shielded peptide NH groups and the characterization of peptide back bone conformational fluctuations. Our initial efforts will focus on using these new methods to obtain integrated structural, conformational and dynamic information on the membrane-active, peptide antibiotics, alamethicin (ALA) and gramidicin-A GRAM-A, in solvents of different polarity and composition and, where feasible, in membrane-memetic environments. From the knowledge and experience gained through these studies we intend to proceed further with these methods to investigate the conformational and dynamic properties of more complex biomacromolecular systems.